A system for traffic monitoring, vehicle speed determination and traffic light violation detection and recording is disclosed. In one embodiment of the current invention, the system is arranged for monitoring traffic supported by a designated surface of a roadway, detecting individual vehicles, measuring vehicle speeds, identifying potential traffic violators, and triggering a traffic imaging device such as a camera or a video system. Different embodiments of the system can also be used by law enforcement agencies and research groups for other applications such as measurement of traffic density, monitoring vehicle speed, and studying traffic patterns. One application of particular embodiments of the current invention is to enforce red light violations. The systems of those embodiments rely on eye-safe laser radiation and scattering of such radiation off the road surface to determine the presence of a vehicle, calculate its speed, determine when a violation is likely to occur (based on predetermined criteria), and trigger the traffic imaging device for collecting evidence of the violation.
Installing traffic monitoring and photo-enforcement systems of prior art customarily involves digging traffic surfaces and pavements in order to install cables for interfacing the violation detecting/recording system with the traffic control devices for synchronization. Such an arrangement, for example, can make a prior art red light photo-enforcement system at least a semi-permanent installation for a specific approach at an intersection. In contrast, the disclosed exemplary embodiments of the current invention do not have a wired connection between a traffic light controller and a system for traffic monitoring in order to communicate the status of the traffic light signal. In some embodiments of the current invention, the state of the traffic signal can be determined remotely by using an optical system coupled to individual detectors or a CCD (charge-coupled device) image recorder as a remote traffic light sensor.
The disclosed embodiments of the system for automated monitoring of traffic patterns, speed measuring, and red light enforcement eliminates the installation costs associated with interfacing by hard wiring the traffic signal controller with conventional Red Light Camera applications. In conjunction with non-intrusive speed quantification technologies (such as laser or video speed sensors), pertinent embodiments of the disclosed systems for monitoring of traffic patterns in accordance with the current invention make it possible to implement an automatic, fully transportable, and autonomous solution. This may be a significant feature for municipalities and police departments who may not decide to install permanent and hard-wired photo-enforcement systems.
Another embodiment of the system according to the current invention includes a mobile monitoring and recording module that can operate in residential areas without disturbing nearby residents or traffic participants. The system module of this embodiment may integrate a lane-specific, laser-based speed measurement device where the laser beams are arranged to impact elongated strips orthogonal to the direction of traffic, detect traffic participants intercepting the elongated strips and determine speeds of the traffic participants having no need to continuously correct the determined speed in accordance to angular relationship between the measuring device and the target traffic participants (“cosine corrections” known in prior art). If any of the traffic participants exceeds and violates a predetermined speed limit, a high-speed visible/infrared (IR) digital camera and an IR flash illuminator are arranged to record images of the violating traffic participant to allow generation of citations both day and night. All sensors of those embodiments may be mounted, for example, on a single erector section, which, in turn, allows the system to be mounted on a wheeled trailer arranged to support and transport the erector section. An exemplary system of this embodiment may be powered by a hybrid electric battery/quiet diesel generator system and requires no hard-wired connections to the local utility infrastructure.